Half eaten sundae at 7am on a Sunday? Certainly within the realm of possibility but not all that probable.

A fair number of military people do not work Monday-Friday, 9-5. When you're doing shift work, you might have the equivalent of breakfast at 5pm or at midnight; basically nothing occurs at what most people would consider a normal time.

Stores and such around military installations tend to support military personnel. I have no problem believing there might have been an unfinished sundae on the counter on a Sunday morning.